package algorithm.dfa;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * @Author shaoxubao
 * @Date 2019/4/25 10:32
 */
public class SensitivewordFilter {

    private Map sensitiveWordMap = null;
    public static int minMatchTYpe = 1;      // 最小匹配规则
    public static int maxMatchType = 2;      // 最大匹配规则

    /**
     * 构造函数，初始化敏感词库
     */
    public SensitivewordFilter() {
        sensitiveWordMap = new SensitiveWordInit().initKeyWord();
    }

    /**
     * 判断文字是否包含敏感字符
     * @param txt  文字
     * @param matchType  匹配规则&nbsp;1：最小匹配规则，2：最大匹配规则
     * @return 若包含返回true，否则返回false
     */
    public boolean isContaintSensitiveWord(String txt,int matchType) {
        boolean flag = false;
        for (int i = 0 ; i < txt.length() ; i++) {
            int matchFlag = this.checkSensitiveWord(txt, i, matchType);  // 判断是否包含敏感字符
            if (matchFlag > 0) {                                         // 大于0存在，返回true
                flag = true;
            }
        }
        return flag;
    }

    /**
     * 获取文字中的敏感词
     * @param txt 文字
     * @param matchType 匹配规则&nbsp;1：最小匹配规则，2：最大匹配规则
     * @return
     */
    public Set<String> getSensitiveWord(String txt , int matchType) {
        Set<String> sensitiveWordList = new HashSet<>();

        for (int i = 0 ; i < txt.length() ; i++) {
            int length = checkSensitiveWord(txt, i, matchType);     // 判断是否包含敏感字符
            if (length > 0) {                                       // 存在,加入list中
                sensitiveWordList.add(txt.substring(i, i + length));
                i = i + length - 1;                                 // 减1的原因，是因为for会自增
            }
        }

        return sensitiveWordList;
    }

    /**
     * 替换敏感字字符
     * @param txt
     * @param matchType
     * @param replaceChar 替换字符，默认*
     */
    public String replaceSensitiveWord(String txt, int matchType, String replaceChar) {
        String resultTxt = txt;
        Set<String> set = getSensitiveWord(txt, matchType);     // 获取所有的敏感词
        Iterator<String> iterator = set.iterator();
        String word = null;
        String replaceString = null;
        while (iterator.hasNext()) {
            word = iterator.next();
            replaceString = getReplaceChars(replaceChar, word.length());
            resultTxt = resultTxt.replaceAll(word, replaceString);
        }

        return resultTxt;
    }

    /**
     * 获取替换字符串
     * @param replaceChar
     * @param length
     * @return
     */
    private String getReplaceChars(String replaceChar, int length) {
        String resultReplace = replaceChar;
        for (int i = 1 ; i < length ; i++) {
            resultReplace += replaceChar;
        }

        return resultReplace;
    }

    /**
     * 检查文字中是否包含敏感字符，检查规则如下：<br>
     * @param txt
     * @param beginIndex
     * @param matchType
     * @return，如果存在，则返回敏感词字符的长度，不存在返回0
     */
    public int checkSensitiveWord(String txt, int beginIndex, int matchType) {
        boolean flag = false;      // 敏感词结束标识位：用于敏感词只有1位的情况
        int matchFlag = 0;         // 匹配标识数默认为0
        char word = 0;
        Map nowMap = sensitiveWordMap;
        for (int i = beginIndex; i < txt.length() ; i++) {
            word = txt.charAt(i);
            nowMap = (Map) nowMap.get(word);                               // 获取指定key
            if (nowMap != null) {                                           // 存在，则判断是否为最后一个
                matchFlag++;                                               // 找到相应key，匹配标识+1
                if ("1".equals(nowMap.get("isEnd"))) {                      // 如果为最后一个匹配规则,结束循环，返回匹配标识数
                    flag = true;                                           // 结束标志位为true
                    if (SensitivewordFilter.minMatchTYpe == matchType) {    // 最小规则，直接返回,最大规则还需继续查找
                        break;
                    }
                }
            } else {     // 不存在，直接返回
                break;
            }
        }
        if (matchFlag < 2 || !flag) {        // 长度必须大于等于1，为词
            matchFlag = 0;
        }
        return matchFlag;
    }

    public static void main(String[] args) {
        SensitivewordFilter filter = new SensitivewordFilter();
        System.out.println("敏感词的数量：" + filter.sensitiveWordMap.size());
        String string = "中国共产党，在五星红旗的号召下高速引进...";
        System.out.println("待检测语句字数：" + string.length());
        long beginTime = System.currentTimeMillis();
        Set<String> set = filter.getSensitiveWord(string, 1);
        long endTime = System.currentTimeMillis();
        System.out.println("语句中包含敏感词的个数为：" + set.size() + "。包含：" + set);
        System.out.println("总共消耗时间为：" + (endTime - beginTime));
    }

}
